|Year : 2020 | Volume
| Issue : 3 | Page : 27-33
A randomized controlled trial to study the effect of hyaluronidase as adjuvant in ultrasound-guided transversus abdominis plane block for postoperative analgesia in total abdominal hysterectomy
Jyoti Petkar1, Sarika S Naik2, Saraswati Devi2
1 Department of Anaesthesiology, Rajarajeshwari Medical College and Hospital (RRMCH), Bengaluru, Karnataka, India
2 Department of Anesthesia and Critical Care, The Oxford Medical College Hospital and Research Center, Bengaluru, Karnataka, India
|Date of Submission||25-Dec-2020|
|Date of Acceptance||22-Jan-2021|
|Date of Web Publication||22-Oct-2021|
Department of Anaesthesiology, Rajarajeshwari Medical College and Hospital, #202, Kambipura, Mysore Road, Bengaluru - 560 074, Karnataka
Source of Support: None, Conflict of Interest: None
Background: Transversus abdominis plane (TAP) block is a regional anesthesia technique for postoperative analgesia. Since multiple nerves are to be blocked in a single prick, mucolytic enzyme hyaluronidase is being used to improve the spread of the local anesthetic. The present study was conducted to evaluate the effect of adding hyaluronidase as an adjuvant to local anesthetic in ultrasound (US)-guided TAP block. Materials and Methods: Eighty patients were randomly divided into two groups, Group B and Group BH. Group B patients received US-guided bilateral TAP block with 38 ml of 0.25% bupivacaine (heavy) and 2 ml of NS. Group BH patients received 38 ml of 0.25% bupivacaine (heavy) with 3000 IU hyaluronidase (2 ml) after completion of surgery under spinal anesthesia. Visual analog score (VAS) and heart rate were noted periodically. Time of demand of the first rescue analgesia and total analgesic consumption in 24 h were noted. Patient satisfaction survey was done at the end of 24 h. Results: Group BH patients had lower mean VAS scores at 6 and 8 h postoperatively as compared to Group B. The mean time of demand for the first rescue analgesia was longer in Group BH (351 ± 16 min) as compared to Group B (307 ± 13 min). The cumulative dose of rescue analgesic needed was more in Group B (370 ± 9 min) as compared to Group BH (343 ± 8 min). Patient satisfaction score was 3.3 ± 0.5 in Group BH and 2.3 ± 0.5 in Group B. All the differences were statistically significant. Conclusion: Addition of hyaluronidase improved quality of postoperative analgesia which can be due to the enzymatic action of hyaluronidase which hydrolyses the hyaluronic acid in the connective tissue and facilitates the spread of local anesthetic solution.
Keywords: Adjuvant, bupivacaine, hyaluronidase, transversus abdominis plane, total abdominal hysterectomy
|How to cite this article:|
Petkar J, Naik SS, Devi S. A randomized controlled trial to study the effect of hyaluronidase as adjuvant in ultrasound-guided transversus abdominis plane block for postoperative analgesia in total abdominal hysterectomy. J Recent Adv Pain 2020;6:27-33
|How to cite this URL:|
Petkar J, Naik SS, Devi S. A randomized controlled trial to study the effect of hyaluronidase as adjuvant in ultrasound-guided transversus abdominis plane block for postoperative analgesia in total abdominal hysterectomy. J Recent Adv Pain [serial online] 2020 [cited 2022 Sep 25];6:27-33. Available from: http://www.jorapain.com/text.asp?2020/6/3/27/329011
| Introduction|| |
Abdominal surgeries cause significant amount of pain in the postoperative period. This can interfere with the early mobilization of patients, can cause postoperative ileus, bilateral basal lung atelectasis, and many other postoperative complications. Regional blocks of the anterior abdominal wall can provide postoperative analgesia and help to prevent these complications.
The transversus abdominis plane (TAP) block was first introduced by Rafi in 2001 as a landmark-guided technique through the triangle of Petit to achieve a field block. TAP block is a regional anesthetic technique that blocks abdominal neural afferents by introducing local anesthetic into the neurofascial plane between the internal oblique and the transversus abdominis muscles. This plane contains the anterior rami of the lower six thoracic nerves (T7 to T12) and first lumbar nerve (L1), supplying the skin, muscles, and parietal peritoneum.,
Ultrasound (US)-guided TAP block is a commonly used postoperative analgesic technique after lower abdominal surgeries.,, Studies have proven that TAP block provides adequate postoperative analgesia for total abdominal hysterectomy surgeries,, when it successfully blocks all of T9 to L1 ventral rami. Spread of drug in the TAP is an important consideration influencing the block. Many adjuvants have been added to local anesthetics to improve the efficiency of peripheral nerve blocks.,, Hyaluronidase is one such additive that has shown promising results.,
The major component of connective tissue is collagen. Depending on the tissue and its function, there are variable arrangements of the collagen bundles. On the contrary, the “ground substance” which surrounds cells comprises proteoglycans. These consist of proteins bound covalently to the glycosaminoglycans: chondroitin-4-sulfate, chondroitin-6-sulfate, and hyaluronic acid. Several of these proteoglycan molecules form an aggregate with hyaluronic acid. Hyaluronic acid is a linear polymer of alternate glycosidic-linked monosaccharides: D-glucuronic acid and 2-acetamido-2-deoxy-D-glucose [Figure 1].
The repeating subunit of hyaluronic acid (disaccharide component) may be shown by the notation.
where GlcNAc = 2-acetamido-2-deoxy-D-glucose, GlcUA = D-glucuronic acid, and the arrows and numbers, respectively, refer to the glycosidic-linkage regions between monomer moieties forming the unbranched, heteropolysaccharide chain. This structure and its inherent hygroscopic nature are responsible for the viscosity and interstitial barrier properties accorded by hyaluronic acid.
The enzyme hyaluronidase cleaves the glycosidic bonds and temporarily depolymerises the repeating disaccharide subunits of hyaluronic acid. This liquefies the interstitial barrier present between cells. It is a short-lived and reversible phenomenon and is dependent on temperature and pH.
By loosening the interstitium, hyaluronidase improves spread of injected substances along tissue planes. However, as is evident with the understanding of connective tissue and the ground substance, spread of substance “across” collagenous barriers (tissue planes) is not affected by hyaluronidase.
Hyaluronidase is hence considered as the “spreading factor,” facilitating the spread of local anesthetic. It also raises the pH of a LA preparation, thereby contributing to the efficacy of LA blockade., It has been shown to produce better quality of block when used with local anesthetics in ophthalmic procedures, plastic surgeries, and orthopedic procedures.,
As TAP block needs to affect several nerves in single tissue plane with a single prick, hyaluronidase is expected to aid greatly in the spread of the LA and help the block.
However, there have not been well-designed studies to establish the efficacy of adding hyaluronidase in lateral TAP after major lower abdominal surgeries. Hence, the present study was carried out to evaluate the efficacy of hyaluronidase as an adjuvant to bupivacaine in US-guided bilateral lateral TAP block.
| Materials and Methods|| |
The study was conducted in the Obstetrics and Gynecology Department of a 750-bedded teaching hospital. Ethical Committee clearance was obtained. The study design was a single-centered prospective double-blinded randomized controlled trail. The study population included female patients undergoing total abdominal hysterectomy, aged between 18 and 65 years, under ASA Grades I and II. Exclusion criteria were hysterectomy for emergency indications, ASA Grades III and IV, age <18 years and >65 years, those with bleeding disorders or on anticoagulants, those with severe respiratory and cardiovascular diseases, history of allergy to local anesthetics, patients with neurologic deficits, patients who are unable to give informed consent, and patients not consenting for the study. Written informed consent was obtained from all the subjects.
Preanesthetic evaluation was done, and investigations in the form of ECG, chest X-ray, complete blood count, renal function tests, and coagulation profile were done. Details of the anesthetic technique and study protocol were explained to the patient during the preoperative visit. Consecutive patients meeting inclusion criteria were divided into two groups using computer generated random numbers.
Group B: USG-guided bilateral TAP block given with 38 ml of 0.25% bupivacaine with 2 ml NS, 20 ml each side.
Group BH: USG-guided bilateral TAP block given with 38 ml of 0.25% bupivacaine with 2 ml (1500 IU) hyaluronidase, 20 ml each side.
In the preoperative room, the nurse-in-charge shall looked up the list of random numbers and attached the corresponding envelope bearing the chit B or BH before shifting inside the OT. In the anesthetic room, patients were connected to the standard monitors and intravenous (IV) fluids were started in 18G IV cannula. Baseline HR, BP, and SpO2 were recorded. All patients were given spinal anesthesia with 26G Quincke–Babcock spinal needle, and 3.5 ml of bupivacaine 0.5% (heavy) was injected after free flow of cerebrospinal fluid. Duration of surgery was noted. Patients requiring supplementary anesthesia or general anesthesia were dropped from the study.
Near the end of surgery, the anesthesiologist prepared 38 ml of 0.25% bupivacaine in a sterile bowl. The anesthesia technician opened the envelope to himself and prepared 2 ml of additive solution accordingly: 2 ml of normal saline if the envelope reads B and 2 ml of hyaluronidase if the envelope reads BH. The additive solution was added to 38 ml of bupivacaine prepared by anesthesiologist. After completion of surgery, before shifting the patient, USG-guided lateral approach TAP block was given bilaterally.
The skin was prepared with 2% chlorhexidine solution, and a high-frequency (6–13 MHz, HFL 38) US probe (SonoSite Fujifilm M-Turbo, Inc.,) was placed transversely on the anterolateral abdominal wall between the iliac crest and the subcostal margin on the right side. The three muscles (external oblique, internal oblique, and transversus abdominis) of the anterior abdominal wall were identified. After identification of the neurofascial plane between the internal oblique and the transversus abdominis muscle, a 23G Quincke–Babcock spinal needle was introduced anteriorly in the plane of the US beam. The needle was directed to approach the TAP, and on entering the fascial plane, 20 ml of the prepared solution was injected after negative aspiration. The injectate was observed spreading in the TAP as a dark oval shape. The procedure was repeated on the contralateral side.
The primary outcome studied was the time of first rescue analgesia and the cumulative analgesia given in 24 h, and the secondary outcome was the patient satisfaction.
After the completion of surgery, patients were shifted to postanesthesia care unit where postoperatively, anesthesia intern on duty recorded in the pro forma, visual analog score (VAS score), and heart rate at 2, 4, 6, 8, 10, 12, 18, and 24 h after the TAP block. Time was noted when VAS score >4 and was started with injection fentanyl infusion at 20 mcg/h as rescue analgesia after consulting anesthesiologist on call and continued for 24 h postoperatively. Adverse effects if any were noted. At the end of 24 h, total amount of analgesic used was recorded. Patient satisfaction score (PSS) was assessed postoperatively at 24 h and was subjectively graded as:
- Excellent – 4
- Good – 3
- Moderate – 2
- Poor – 1.
After 24 h, the principal investigator recovered the pro forma and the envelope and entered the data in the respective group.
Sample size estimation
The sample size was estimated from difference in the mean postoperative time of first analgesic demand (min) from the study Karim Y et al. Using these values at 95% confidence limit and 90% power, sample size of 36 was obtained in each group. With 10% nonresponse, sample size of 36 + 36 was estimated. Therefore, 40 cases were included in each group.
Data were entered into Microsoft Excel data sheet and analyzed using SPSS (Version 22.0; IBM Corporation, Armonk, NY, USA). Categorical data were represented in the form of frequencies and proportions. Chi-square was the test of significance. Continuous data were represented as mean and standard deviation. Independent t-test was the test of significance to identify the mean difference between two groups. P < 0.05 was considered as statistically significant.
| Results|| |
Eighty patients were included in the study. There were no significant differences in demographic data and duration of surgery [Table 1]. Two patients in Group B required supplementary anesthesia with injection fentanyl and injection ketamine, and in Group BH, one patient required general anesthesia and another patient required supplementation with injection fentanyl. Hence, two patients in Group B and two patients in Group BH were excluded from the study [Figure 2] consort diagram].
Group BH patients had significantly lower mean VAS scores [Figure 3] at 6 and 8 h postoperatively as compared to Group B [Table 2]. Group BH patients had lower mean heart rate [Figure 4] at 6, 8, and 10 h as compared to Group B which was statistically significant [Table 3]. The mean time of demand for the rescue analgesia with injection fentanyl infusion of 20 mcg/h [Figure 5] in Group BH was 351.32 ± 15.97 min as compared to Group B which was 307.76 ± 13.19 min and the difference was statistically significant. However, the cumulative dose of rescue analgesic injection fentanyl needed [Figure 6] was more in Group B (370.11 ± 8.72 min) as compared to Group BH (343.13 ± 8.40 min) and was statistically significant [Table 4].
Patient satisfaction survey [Figure 7] showed the scoring of 3.32 ± 0.53 in Group BH and 2.32 ± 0.53 in Group B and the difference was statistically significant showing the Group BH patients who were more satisfied as compared to Group B. There were no complications related to the block procedures and no signs or symptoms of local anesthetic toxicity.
| Discussion|| |
Major abdominal surgeries require optimal analgesia for adequate postoperative recovery. Abdominal wall blocks have become popular as regional analgesia technique ensuring pain-free postoperative period encouraging early mobilization and preventing postoperative complications such as deep vein thrombosis as also side effects associated with opioids. So regional anaesthesia is preferred to avoid the complications related with systemic opoids. In this present study, mean VAS scores at 6th h and 8th h were significantly low with hyaluronidase indicating the improved quality of block. Vitals noted showed a significantly lower mean heart rate at 6, 8, and 10 h postoperatively which also supports the better quality of block which can be attributed to the better spreading effect of hyaluronidase. PSS also showed the better quality of block in Group BH.
Lewis Smith studied the hyaluronidase as an adjunct to lignocaine by subcutaneous infiltration in the volar aspect of a volunteer's forearm and found that in hyaluronidase group, the onset of anesthesia was immediate and spread of infiltrate was very rapid. Although hyaluronic acid contributes only 2% of whole tissue flow resistance, the effect of hyaluronidase in reducing the tissue resistance is far greater than might be expected which may be due to the fact that it hydrolyses not only hyaluronic acid but also chondroitin sulfate, another component of ground substance.
Johnson and O'Connor monitored the serum lignocaine levels after subcostal TAP block with hyaluronidase during laparoscopic cholecystectomy. He found that the addition of hyaluronidase did not lead to elevated serum lignocaine above the safe levels while excellent postoperative analgesia with addition of hyaluronidase. This has reassured the safety with regard to local anesthetic toxicity. In our study, there were no complications suggestive of local anesthetic toxicity.
Karim et al. studied the effect of adding hyaluronidase to local anesthestics in US-guided supraclavicular brachial plexus block and found that the use of hyaluronidase reduced the time to reach the complete sensory block and motor block thereby reducing the total anesthetic time before operation. However, it had little effect on total analgesic duration and on the consumption of postoperative analgesia. In contrast to this, in our study, we found that the total analgesic consumption in the 1st postoperative day was lesser in Group BH as compared to Group B which can be attributed to improve quality of analgesia in hyaluronidase group.
Bala Bhaskar et al. studied the effect of adding hyaluronidase to bupivacaine in US-guided TAP block for inguinal hernia repair under general anesthesia where unilateral TAP block was given before extubation and found the significant reduction in Numerical Rating Scale at cough and attributed it to the improved quality of analgesia as a result of increased spread due to hyaluronidase. In our study also, we found similar results showing significantly low VAS scores at 6 and 8 h which can be attributed to the spreading effect of hyaluronidase. In addition, the mean heart rate was low at 6, 8, and 10 h as compared to Group B and was statistically significant indicating the better quality of block in hyaluronidase group. Patient satisfaction survey at the end of 24 h showed that the patients in Group BH were more satisfied than Group B showing the improved quality of analgesia in the postoperative period due to hyaluronidase.
Schulenburg et al. studied the effect of adding hyaluronidase to local anesthetic for Sub-Tenon's anesthesia and concluded that addition of hyaluronidase significantly reduced the volume of local anesthetic that is required for a satisfactory surgical field. Moore et al. also found that besides hastening the onset of analgesia, when hyaluronidase was added, adequate blocks could be established with smaller volumes of anesthetic solutions. Similarly, Chaudhari and Chaudhari studied the effect of adding hyaluronidase with local anesthetic agents in inguinal hernia block and found that the group in which hyaluronidase was added required less intraoperative analgesia as compared to group with only local anesthetics without hyaluronidase. In the present study, although we did not try to reduce the total volume of local anesthetic used, the patient satisfaction survey showed that patients with hyaluronidase were more comfortable at the end of 24 h as compared to group without hyaluronidase which can be attributed to the better spread of the local anesthetic in hyaluronidase group. These experiences shall aid in managing patients where the permitted dosage of local anesthetic and/or analgesic is restricted.
Chaudhari and Chaudhari also found that the mean duration of analgesia was significantly longer in hyaluronidase group and pain scores at 2 and 6 h were lower in hyaluronidase group which was statistically significant. They concluded that hyaluronidase with local anesthetic agent for inguinal hernia block provides excellent intraoperative analgesia and also prolongs the postoperative analgesia. In our study also, we found similar results where the VAS scores were significantly lower at 6 and 8 h in hyaluronidase group, and furthermore, the time of demand for the first rescue analgesia was longer in hyaluronidase group and cumulative dose of rescue analgesia was less in hyaluronidase group which showed that hyaluronidase prolongs the postoperative analgesia.
Mohamed et al. studied the efficacy of addition of hyaluronidase to a mixture of lidocaine and bupivacaine in scalp nerve block in elective craniotomy operations and concluded that addition of hyaluronidase to the local anesthetic mixture improves the success rates of scalp nerves block and its efficacy especially during stressful intraoperative periods and in early postoperative period. In this study, the VAS scores were significantly lower in hyaluronidase group starting from 30 min to 6 h postoperative. In the current study also, we found the similar result where VAS scores were low at 6 and 8 h postoperatively which showed the favorable analgesic effects of adding hyaluronidase to local anesthetics.
However, there have been some contradictory findings too. Keeler et al. studied the effect of addition of hyaluronidase to bupivacaine in brachial plexus block. They reported shorter duration of postoperative analgesia in hyaluronidase group, and this was attributed to the enhanced absorption of the anesthetic with addition of hyaluronidase. Koh et al. added hyaluronidase to ropivacaine in axillary brachial plexus block . However he found no significant difference in the intraoperative and postoperative doses of opiods consumption in ropivacaine with hyaluronidase group as compared to plain ropivacaine group. Such findings that are different from the present study may be attributed to differences in anesthetic agents, dosages, and different techniques of anesthesia.
There were limitations in the present study. Since the patients were given spinal anesthesia for the procedure, it was more difficult to recognize insufficient analgesia in the immediate postoperative period.
| Conclusion|| |
The present study shows that the use of hyaluronidase as an adjuvant to local anesthetics in US-guided TAP block provides excellent postoperative analgesia in total abdominal hysterectomy surgeries. Addition of hyaluronidase also delays the need for rescue analgesia and reduces analgesic consumption in immediate postoperative period.
The authors would like to thank Dr. Ramesh Gudur, HOD of OBG Department and all the colleagues of OBG Department of The Oxford Medical College and Hospital for their help in the research. We also thank the Interns of The Oxford Medical College for helping us in collecting the postoperative data.
This is to state that the manuscript has been read and approved by all the authors, that the requirements for authorship as stated earlier in this document have been met, and that each author believes that the manuscript represents honest work.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Yarwood J, Berrill A. Nerve blocks of the anterior abdominal wall. Contin Educ Anaesth Crit Care Pain 2010;10:6.
Rafi AN. Abdominal field block: A new approach via the lumbar triangle. Anaesthesia 2001;56:1024-6.
Tsai HC, Yoshida T, Chuang TY, Yang SF, Chang CC, Yao HY, et al
. Transversus abdominis plane block: An updated review of anatomy and techniques. Biomed Res Int 2017;2017:8284363. Doi: 10.1155/2017/8284363.
Hebbard P, Fujiwara Y, Shibata Y, Royse C. Ultrasound-guided transversus abdominis plane (TAP) block. Anaesth Intensive Care 2007;35:616-7.
Ripollés J, Mezquita SM, Abad A, Calvo J. Analgesic efficacy of the ultrasound guided blockade of the transversus abdominis plane – A systematic review. Braz J Anesthesiol 2015;65:255-80.
Brogi E, Kazan R, Cyr S, Giunta F, Hemmerling TM. Transversus abdominal plane block for postoperative analgesia: A systematic review and meta-analysis of randomized controlled trials. Can J Anesth 2016;63:1184-96.
Abdallah FW, Laffey JG, Halpern SH, Brull R. Duration of analgesic effectiveness after the posterior and lateral transversus abdominis plane block techniques for transverse lower abdominal incisions: A meta-analysis. Br J Anaesth 2013;111:721-35.
Mishriky BM, George RB, Habib AS. Transversus abdominis plane block for analgesia after Cesarean delivery: A systematic review and meta-analysis. Can J Anaesth 2012;59:766-78.
Champaneria R, Shah L, Geoghegan J, Gupta JK, Daniels JP. Analgesic effectiveness of transversus abdominis plane blocks after hysterectomy: A meta-analysis. Eur J Obstet Gynecol Reprod Biol 2013;166:1-9.
Zhou H, Ma X, Pan J, Shuai H, Liu S, Luo X, et al
. Effects of transversus abdominis plane blocks after hysterectomy: A meta-analysis of randomized controlled trials. J Pain Res 2018;11:2477-89.
Carney J, Mcdonnell JG, Ochana A, Bhinder R, Laffey JG. The transverses abdominis plane block provides effective postoperative analgesia in patients undergoing total abdominal hysterectomy. Anesth Analg 2008;107:2056-60.
Bala Bhaskar S, Shetty P, Chand NK. Ultrasound guided transversus abdominis plane block for inguinal hernia repair: Does addition of hyaluronidase to bupivacaine affect postoperative analgesia? Anesth Analg 2016;123:611.
Wang LZ, Liu X, Zhang YF, Hu XX, Zhang XM. Addition of fentanyl to the ultrasound-guided transversus abdominis plane block does not improve analgesia following cesarean delivery. Exp Ther Med 2016;11:1441-6.
Kartalov A, Jankulovski N, Kuzmanovska B, Zdravkovska M, Shosholcheva M, Spirovska T, et al
. Effect of adding dexamethasone as a ropivacaine adjuvant in ultrasound-guided transversus abdominis plane block for inguinal hernia repair. Pril (Makedon Akad Nauk Umet Odd Med Nauki) 2015;36:35-41.
Luan H, Zhang X, Feng J, Zhu P, Li J, Zhao Z. Effect of dexmedetomidine added to ropivacaine on ultrasound-guided transversus abdominis plane block for postoperative analgesia after abdominal hysterectomy surgery: A prospective randomized controlled trial. Minerva Anestesiol 2016;82:981-8.
Johnson MZ, O'Connor TC. Excellent postoperative analgesia with the addition of hyaluronidase to lignocaine for subcostal TAP block used in conjunction with systemic analgesia for laparoscopic cholecystectomy. BMJ Case Rep 2014:1-3. doi:10.1136/bcr-2013-202911.
Chaudhari AV, Chaudhari VP. Local anaesthetic agents along with hyaluronidase for inguinal hernia block provides excellent analgesia: A double blind study. Int J Basic Clin Pharmacol 2013;2:466-9.
Watson D. Hyluronidase. Br J Anaesth 1993;71:422-5.
Buhren BA, Schrumpf H, Hoff NP, Bölke E, Hilton S, Gerber PA. Hyaluronidase: From clinical applications to molecular and cellular mechanisms. Eur J Med Res 2016;21:5.
Stern R, Jedrzejas MJ. Hyaluronidases: Their genomics, structures, and mechanisms of action. Chem Rev 2006;106:818-39.
Roberts JE, MacLeod BA, Hollands RH. Improved peribulbar anaesthesia with alkalinization and hyaluronidase. Can J Anaesth 1993;40:835-8.
Moore DC. The use of hyaluronidase in local and nerve block analgesia other than spinal block: 1520 cases. Anesthesiology 1951;12:611-26.
Schulenburg HE, Sri-Chandana C, Lyons G, Columb MO, McLure HA. Hyaluronidase reduces local anaesthetic volumes for sub-Tenon's anaesthesia. Br J Anaesth 2007;99:717-20.
Lewis Smith PA. Adjunctive use of hyaluronidase in local anaesthesia. Br J Plast Surg 1986;39:554-8.
Pettersson LO, Akerman B. Influence of hyaluronidase upon local infiltration anaesthesia by lidocaine. An experimental study in the guinea-pig. Scand J Plast Reconstr Surg 1984;18:297-301.
Karim Y, Kamal Hakim, Mohamed Awad Al Saeid Ahmed et al. Effect of addition of hyaluronidase as an adjuvant to local anesthetics in ultrasound guided supraclavicular brachial plexus block. Ain Shams J Anaesthesiol 2017;10:213-8.
Mohamed AA, Radwan TA, Mohamed MM, Mohamed HA, Mohamed Elemady MF, Osman SH, et al
. Safety and efficacy of addition of hyaluronidase to a mixture of lidocaine and bupivacaine in scalp nerves block in elective craniotomy operations; Comparative study. BMC Anesthesiol 2018;18:129.
Keeler JF, Simpson KH, Ellis FR, Kay SP. Effect of addition of hyaluronidase to bupivacaine during axillary brachial plexus block. Br J Anaesth 1992;68:68-71.
Koh WU, Min HG, Park HS, Karm MH, Lee KK, Yang HS, et al
. Use of hyaluronidase as an adjuvant to ropivacaine to reduce axillary brachial plexus block onset time: A prospective, randomised controlled study. Anaesthesia 2015;70:282-9.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
[Table 1], [Table 2], [Table 3], [Table 4]